1. Field of the Invention
The present invention relates to a method of and an apparatus for chopping into pieces runners ahd sprues discharged from an injection molding machine in an apparatus for manufacturing slide fastener chains having molded coupling elements of synthetic resin.
2. Description of the Prior Art
There are known apparatus for manufacturing slide fastener chains by injection-molding a plurality of coupling elements of synthetic resin simultaneously on a pair of slide fastener stringer tapes. Since the injection-molded coupling elements are interconnected by a runner which is formed in a feed channel or runner in a mold, the molded runner is required to be cut off as disclosed in Japanese Patent Publications 39-9385 and 38-20921. The molded runners discharged from the injection molding machine in the apparatus are collected for reuse. More specifically, the runner is cut off by a cutter into pieces 5 to 6 cm long, which are then chopped as by a crusher into smaller chips having a length of about 3-5 mm that will be fed again into the injection molding machine. However, the prior chopping process requires two devices, the cutter and the crusher, and an expenditure of manual labor for carrying the broken pieces from the cutter to the crusher and operating the crusher. The crusher scatters the chopped pieces resulting in a loss of reusable material and contaminates surroundings with the scattered chips. When a differently colored runner is to be processed, the cutter and the crusher have to be cleaned.